Advice and News, Hints & Tips •

Split System vs Ducted Running Costs

Air conditioners are a necessity in Australia, and if you’re considering a new system for your home, it can be tough to decide between split and ducted. Ducted systems are luxurious, tucked away neatly, and incredibly versatile. On the other hand, split systems are affordable, and can give you a lot of cooling bang for your buck, particularly for smaller homes.

So let’s take a look at the main arguments for each, with a comprehensive breakdown of split system vs ducted running costs.

Running costs by kWh

Split system

In Brisbane, a 2.5kW split system will consume an average of 511kWh in energy when used for cooling, which equates to annual running costs of about $110.

If you increase the size of the split system to 5kW, you’re looking at annual consumption of around 819kWh, which costs around $180.00. That leaps up to 1,284kWh and $280 for a unit of up to 6kW. Considering Brisbane’s sweltering summer, these figures are reasonable.


Ducted air conditioning running costs can be estimated using the energy star label on your air conditioner. The energy star label should list the “power input” of the air conditioner in kilowatts. Take the provided power input and multiply it by the kilowatt hour (kWh) cost listed on your last electricity bill. This will give you the cost per hour for running your ducted air conditioner.

For example, if the power input listed on the energy star rating label is 2.6, and the kilowatt house cost on your last electricity bill is $0.35/kWh, the cost per hour for running your ducted air conditioner would be $0.91 per hour (2.6 x 0.35 = 0.91).

Note: These figures are examples only—the actual running cost of your ducted air conditioner will vary based on the power input, your electricity cost, and more. Predicting AC running costs is notoriously difficult due to the number of variables involved.

Cost by bedroom

A standard reverse cycle split system air conditioner costs about 35 – 70 cents per hour when cooling an average room of 36m2. That means costs of about $1.05 to $2.10 per hour if you want to cool a three bedroom home. That cost increases $1.40 to $2.80 per hour if you want to cool an average home of three bedrooms, while also running a split system air conditioner in your living space.

Ducted air conditioners consume approximately $2.45 to $3.45 in power to cool the same area, which equates to costs of roughly $0.83 – $1.15 per hour, per room, in a three bedroom home. This isn’t the whole story though, because modern ducted air conditioners use zoning technology can cut down considerably on those costs by cooling only the rooms that are in use. That means, for example, that you can cool just one bedroom of your house and conserve the energy that would have otherwise gone into the two other bedrooms.

Brand considerations

Brands are a big deal when it comes to the split system vs ducted argument, and that’s because only the high-quality brands are able to offer optimal running costs—especially in ducted systems. Daikin, for example, offers ducted zoning technology which can drastically reduce running costs. Similarly, Fujitsu and Mitsubishi Electric offer three phase and single phase—both with zoning compatibility—for higher energy efficiency.

Zoning technology has brought ducted air conditioners a long way in the running costs debate, as it allows for cooling zones to be switched off. Essentially, if a room doesn’t need to be cooled, your air con’s zoning technology will turn it off to conserve energy. When the room is in use, the zone activates again.

With split systems, brands are less of an issue. Because they’re so popular, most split system manufacturers are competitive in terms of energy efficiency. As with all products, there are still low-quality models with poor running costs and even poorer performance. However, they’re pretty easy to avoid with some expert input.

Temperature optimisation

It is estimated that every degree of temperature that your air conditioner has to cool, its running costs increase by up to 15%. Temperature optimisation is the key to competitive running costs in ducted and split system air conditioners alike, and with the addition of intelligent, smart-controlled zones, ducted air conditioners have become much more efficient.

New vs old

It goes without saying that new air conditioners with the latest inverter technology are more efficient and cheaper to run than old ones. Ducted air conditioners are expected to last longer because of the time, cost, and difficulty associated with installing them, which means there are probably more older ducted units being used compared to split systems, which can be revealed in the power bill. But as long as you have a reasonably modern ducted system, you shouldn’t have this problem.

Smart home advantages

Smart home technology has vaulted ducted air conditioning into a competitive position in recent years, and that’s thanks to zoning technology and smart phone compatibility. Ducted air conditioners are far ahead in technological innovation—with smart home technology, you can remotely isolate rooms that aren’t in use, control individual zone temperatures which alleviates the work your ducted unit has to do to maintain the temperatures you set.

In addition, you can adjust your temperatures, zoning, and general operation from any location with internet access. If you forget to turn your air conditioner off when you leave for work, you can simply turn it off on the move. If you prefer to leave your ducted air conditioner running to maintain a certain temperature, you can increase that temperature to save power when you’re absent, and reduce it again before you return, so that your living space is comfortable on arrival.

Maintenance and running costs

When air conditioners are poorly maintained, dust and debris accumulates within the filters, fan coils ,ducts, and vents. Over time, they make it harder for the components within your air conditioner to function properly. And of course, when its components aren’t functioning properly your air conditioner will need to work harder to maintain the set temperature. Hard work equates to electricity consumption, which then equates to cost. That’s why ducted air conditioner maintenance has a big effect on overall running costs.


In humid, mould-thriving environments, both split and ducted air conditioners can experience increased running costs, even with regular maintenance. Unlike dust, mould is a living organism, which means simply wiping it off won’t always do the job. Once mould spores lodge themselves in your air conditioner, getting rid of them involves specialised products, and often professional help.

Long term vs short term savings

Ducted air conditioners are more expensive to install than split systems, but are more versatile, long-lasting, and aesthetically pleasing. If you’re looking for a cheap and quick air conditioning solution for just one or two rooms, a well-sized split system is probably the way to go. But if you’re looking for a more complete solution that will last longer and potentially increase the value of your house, a ducted system is best. And for heavy duty commercial applications, ducted air conditioning represents the most cost-effective option in the long and short terms (more on this below).

Commercial vs domestic

Ducted air conditioners are the undisputed kings of commercial air conditioning. Their running costs are far better that those of split systems, given the vast spaces that they need to cool. Split system air conditioners don’t come in sizes large enough to cater for large warehouses, shopping centres, and other such commercial spaces. That means that if you were to use one (or a few) for those applications, they would be overworked, and overwork means inefficiency. The harder you force a split system air conditioner to work, the more energy it consumes, and that translates directly in its running costs.

The next component is effectiveness: can a small split system realistically cool a large space? In a lot of commercial settings they can’t, and that means that they are constantly trying to cool a room to a temperature they can never attain. Not only will this consume a massive amount of power, but it will also burn out the unit much quicker. That leaves you with higher running costs, frequent maintenance or replacement outlays, and a hot room.

Purpose-built commercial ducted systems, on the other hand, have powerful units and well-insulated ducting. They don’t need to work as hard to bring the temperature down, and they require less work still to keep them there. You’ll often find that ducted systems run all day and night in commercial spaces too, and that’s because some models use less energy maintaining a temperature than they do to reach that temperature in the first place. So, rather than make the air conditioner work to lower the temperature every morning, they are simply set to maintain an ambient temperature indefinitely.

Why are ducted systems more expensive to install?

Much of the cost associated with ducted air conditioning is due to installation. They look great because the ducts are all hidden from sight and the outlets are low profile vents in the ceiling, wall, or (sometimes) floor. But that is not easy to achieve, and technicians will need to move through your roof cavities for hours on end to get the ducting in place, before connecting the whole system to the air conditioning unit itself.

Split system vs ducted air conditioning: the conclusion

If you’re interested in gross running costs alone, then split systems are the way to go. They are cheap to buy, cheap to install, and cheap to run when compared to their ducted counterparts. However, air conditioning is not a one size fits all undertaking; each air conditioner needs to perfectly suit its location and its purpose. If you get that wrong, then you will be left with an inefficient air conditioning solution, which will translate directly to poor performance and higher running costs.

So, before you decide between a split or ducted system, think about what’s unique with your situation. Are you trying to cool three or more rooms in your home, or need to cool a commercial space? If so, there’s plenty that ducted air conditioning can offer you. In fact, it’s probably the case that split systems simply won’t offer you the results you need.

On the other hand, if you’re looking to air conditioner a single bedroom or even a standard lounge room, a ducted air conditioner is probably not feasible.

Ducted Air Conditioning requires plenty of roof space so that your air conditioning technicians can actually access the spaces they need to access for the installation to take place.

It’s easy for a professional to assess your circumstances in a residential setting. However, in commercial settings getting the right air con solution is far more complex. It’s worth taking the time to get it right, so that your air conditioner isn’t left straining to keep you cool, and using more power than it has to in the process.

Call H & H Air Conditioning on (07) 3276 1800 (Brisbane) or (07) 5477 1777 (Sunshine Coast) for your on site appraisal.